We are all familiar with tree/”folder”-based organization schemes, in which items are grouped in progressively more specific categories, with each single item or sub-category belonging to ONE larger category. However, there are quite some instances where it would be useful to allow each category to have MULTIPLE “parents”. For instance, one might want to categorize a paper about an image processing algorithm under both a “photography” category and a “programming” category, or a photo of a bird taken on vacation in Africa to be categorized under both “Africa vacation” and “wildlife”, and have it be equally findable browsing either of these categories. The tree model necessarily requires prioritizing one classification over the other, or keeping multiple copies of items.
This problem seems obvious enough that I’d think someone would have already come up with a name, standard logical scheme, and implementation(s) for such a “non-exclusive classification”. There are a few limited cases where I know such a thing DOES exist, like in photo apps where tags are assigned to images non-exclusively. I’m wondering, though, if there are good general apps that sit “on top of” the underlying filesystem’s tree structure (which will almost certainly always remain a tree for practicality and backward compatibility reasons) and present a non-exclusive classification metaphor to the browsing user. In “providing such a metaphor”, I mean allow navigation to an item from any category of which it is a member, and when an item is found, being able to see the other categories it’s in (other than the one used to find it)
The specific concrete situation that prompted this was browser bookmarks in Chrome, so in particular I’d be interested in if a browser extension implementation exists, but there are quite some other non-browser contexts where this would be very useful as well.
